All About Mammals
As of 2006, approximately 5,500 species of mammals have been recorded on Earth. This sounds like a lot, but when you consider there are more than 28,000 kinds of fish and over 1,000,000 kinds of insects, you'll realize mammals are a pretty small class!
The temperature could be freezing cold or boiling hot, but mammals' bodies are built to maintain just about the same temperature all the time. Warm blood lets the mammals be very active and live in a wide variety of places.
Mammals can be found almost everywhere. Polar bears live in very cold areas. Camels live in hot areas. Moles live under the ground. Bats live in caves and fly in the air. Dolphins live in the oceans. Fur and fat help protect mammals who live in the cold. Mammals sweat or pant to release extra heat if they live somewhere toasty.
Except for the platypus and the echidna which lay eggs, all mammals give birth to live young. Many mammal babies are helpless, but some, such as zebras and moose, can walk on the day they are born.
All mammal mothers feed their babies milk. A cow feeds her calf cow milk just as a right whale feeds her baby whale milk, and a hamster feeds her babies hamster milk.
The Blue Whale, Balaenoptera musculus, is the largest mammal living today. It is also the largest mammal to have ever lived. In fact the Blue whale is the largest animal ever to have lived on the planet as far as we know; bigger by far than ever the largest Dinosaur. The longest Blue Whale ever measured was a female, 110 feet long. The heaviest weighed over 419,000 pounds.
The largest animal on land at the moment on this planet is a mammal; the bull African Elephant. The largest specimen recorded stood around 13 feet at the shoulder and weighed over 26,500 pounds.
The largest land mammal to have ever existed is believed to be the Indricotherium. This extinct mammal stood 17 feet at the shoulder and was thought to weigh as much as 33,000 pounds.
The tallest animal on the planet is a mammal - Giraffes, Giraffa camelopardalis, can be 20ft tall.
The smallest mammal in the world is a bat from Thailand, Kitli's Hog-nosed Bat, Craseonycteris thonglongyai, being only 1.14 inches long and weighing a mere 0.06 - 0.07oz this bat is well smaller than many insects and snails.
In a close 2nd place, the Pygmy or Savi's White-toothed Shrew Suncus etruscus weighs in at 0.05 - 0.09oz and is definitely the smallest land mammal on record.
The Cheetah, Acinonyx jubatus, is the fastest animal on land, reaching speeds as fast as 60 mph. The fastest mammal in the water is the Killer Whale, Orcinus orca, which has been recorded swimming at speeds of 34 mph. The fasted mammal in the air is the Big Brown Bat, Eptesicus fuscus, with a recorded flight speed of 15.5 mph.
The longest lived mammals are human beings, but the whales are not far behind us and the Fin Whale Balaenoptera physalis is believed to have a maximum life-span of 90 - 100 years.
Rhinoceroses Dicerorhinus sumatrensis have the thickest skin of any terrestrial mammal, and the thickest skin in relation to their size, of any animal. The skin on their backs and flanks can be 1 inch thick.